JP6852597B2 - Control device, control method, program - Google Patents

Description

The present invention relates to communication technology, and more particularly to control devices, control methods , and programs for controlling channels.

An uplink / downlink pair of radio frequencies is assigned to a digital radio system consisting of two types of equipment, a base station and a mobile station. In a digital radio system, communication between a base station and a mobile station or between mobile stations via a base station is performed using a pair of upstream and downstream radio frequencies. The mobile station is in the transmitting state by press talk, and the information transmitted from the mobile station is transmitted to other mobile stations in the receiving state in the base station zone via the base station.

However, even if the base station is in the transmitting state, there are mobile stations that cannot receive communication from the base station because the received electric field strength is not at a level that can be demodulated. In order to send information to such a mobile station, the base station determines a first mobile station that cannot receive information from the base station and a second mobile station that is close to the first mobile station. .. The base station instructs the second mobile station to transmit predetermined information to the first mobile station in place of the transmission frequency of the base station for a certain period of time. Upon receiving the instruction, the second mobile station transmits the information to the first mobile station (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-86923

When the second mobile station is made to transmit predetermined information to the first mobile station in place of the transmission frequency of the base station for a certain period of time, the second mobile station, that is, the mobile station The process becomes complicated. Further, when there are a mobile station capable of executing such a complicated process and a mobile station that cannot execute the process, the non-executable mobile station cannot be set as the second mobile station, so that the process may not be executed. is there.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a technique for suppressing the occurrence of a situation in which a terminal device cannot communicate while avoiding complication of processing of the terminal device.

In order to solve the above problems, the control device of an embodiment of the present invention is a detection unit that detects the quality of a signal received by a first base station device and a signal from a terminal device using the first channel. When the detection unit detects a signal quality deterioration, the reception channel of the second base station device is changed from the second channel to the first channel, and the transmission channel of the second base station device is not changed . To be equipped.
Another aspect of the invention is also a control device. This device includes a detector that detects the quality of the signal received by the first base station device and the signal from the terminal device that uses the first channel.
When the detection unit detects a signal quality deterioration, it includes a setting unit that changes the reception channel of the second base station apparatus from the second channel to the first channel. The setting unit returns the reception channel of the second base station device from the first channel to the second channel when a predetermined time has elapsed after the second base station device changes the reception channel.
Yet another aspect of the present invention is also a control device. This device is a signal received by the first base station device, and when the detection unit detects the quality of the signal from the terminal device using the first channel and the detection unit detects the deterioration of the signal quality. , A setting unit for changing the reception channel of the second base station apparatus from the second channel to the first channel is provided. The setting unit calculates the total value or the average value of the priorities of the terminal devices received within the past predetermined time in the second base station device, and the priority of the terminal device to be detected in the detection unit is higher than the calculated value. If it is high, the reception channel of the second base station apparatus is changed from the second channel to the first channel.

Yet another aspect of the present invention is a control method. This method is a control method used for a control device, that is, a step of detecting the quality of a signal received by a first base station device and a signal from a terminal device using the first channel, and a signal. This includes a step of changing the reception channel of the second base station apparatus from the second channel to the first channel when a quality deterioration is detected. The changing step does not change the transmission channel of the second base station apparatus .
Yet another aspect of the invention is also a control method. This method is a control method used for a control device, which is a detection step for detecting the quality of a signal received by the first base station device and a signal from a terminal device using the first channel, and detection. This includes a change step of changing the reception channel of the second base station apparatus from the second channel to the first channel when a signal quality deterioration is detected in the step. The change step returns the reception channel of the second base station apparatus from the first channel to the second channel when a predetermined time has elapsed since the second base station apparatus changed the reception channel.
Yet another aspect of the invention is also a control method. This method is a control method used for a control device, which is a detection step for detecting the quality of a signal received by the first base station device and a signal from a terminal device using the first channel, and detection. This includes a change step of changing the reception channel of the second base station apparatus from the second channel to the first channel when a signal quality deterioration is detected in the step. In the change step, the total value or the average value of the priorities of the terminal devices received within the past predetermined time in the second base station device is calculated, and the priority of the terminal device to be detected in the detection step is higher than the calculated value. If it is high, the reception channel of the second base station apparatus is changed from the second channel to the first channel.

It should be noted that any combination of the above components and the conversion of the expression of the present invention between methods, devices, systems, recording media, computer programs and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to suppress the occurrence of a situation in which the terminal device cannot communicate while avoiding the complicated processing of the terminal device.

It is a figure which shows the structure of the communication system which concerns on Example 1. FIG. It is a figure which shows the arrangement of the channel used in the communication system of FIG. It is a figure which shows the outline of the process when the channel arrangement of FIG. 2 is used. It is a figure which shows the structure of the base station apparatus of FIG. It is a figure which shows the structure of the control device of FIG. It is a figure which shows the table of CH stored in the storage part of FIG. It is a figure which shows the base station apparatus detailed information table stored in the storage part of FIG. It is a figure which shows the terminal reception history table stored in the storage part of FIG. It is a figure which shows the outline of the processing by the control device of FIG. It is a figure which shows the outline of the continuation processing by the control device of FIG. It is a figure which shows the outline of the further processing by the control device of FIG. It is a flowchart which shows the processing procedure by the control device of FIG. It is a figure which shows the priority table which is stored in the storage part which concerns on Example 2. FIG. It is a flowchart which shows the processing procedure by the control apparatus which concerns on Example 2.

(Example 1)
Before explaining the present invention in detail, first, an outline will be given. The first embodiment of the present invention relates to a communication system including a plurality of terminal devices that communicate with each other via a base station device. This communication system corresponds to, for example, a commercial wireless system and executes group communication. Further, the frequency of the uplink from the terminal device to the base station device (hereinafter referred to as “upstream frequency”) and the frequency of the downlink from the base station device to the terminal device (hereinafter referred to as “downstream frequency”) are different. The uplink frequency corresponds to the reception frequency in the base station apparatus, and the downlink frequency corresponds to the transmission frequency in the base station apparatus. Although a plurality of uplink frequencies and a plurality of downlink frequencies are specified, a combination of one uplink frequency and one downlink frequency is set in the base station apparatus. Hereinafter, this combination may be referred to as a "channel", but either the uplink frequency or the downlink frequency may be referred to as a "channel". In addition, "channel" may be described as "CH". Also, the CH is different for each group. A plurality of base station devices are connected to a control device, and the control device controls each base station device, and when the base station device receives call information (transmission information) from the terminal device, the base is concerned. The received call information is transferred to another base station device that uses the same CH as the station device. This corresponds to the execution of group communication across a plurality of base station devices.

In commercial wireless systems, there are many operations in which the CH to be used is determined for each group. Therefore, the CH set in the base station apparatus cannot be easily changed to the CH used in another group. Therefore, if the terminal device goes out of the communication area while transmitting call information within the communication area of the base station device that uses the CH of the group to which it belongs, it must be in another communication area that uses the CH. If this is the case, the call information will not be received by the base station device. This interrupts communication. Therefore, it is desired that the call information is not interrupted even if the communication area of the base station apparatus in which the usable CH is set is temporarily removed. That is, it is desired that the call information is communicated without interruption of sound even when the terminal device moves across the communication area.

When the control device according to the present embodiment detects that the terminal device transmitting the call information is about to leave the communication area, one or more of the control devices forming a continuous communication area with the communication area. Look for other base station equipment. At that time, the position information of the terminal device is not used, and the installation position information of the base station device and the radius of the communication area, which are not easily moved once installed, are used. If the other base station device has not received the call information from the other terminal device and is using a CH different from the CH used by the terminal device, the control device is the other base. The uplink frequency used by the station device is changed to the uplink frequency of the CH used by the terminal device. That is, another base station device that is not currently receiving or is not receiving within a predetermined time is temporarily used. On the other hand, the downlink frequencies of other base station devices cannot be switched.

FIG. 1 shows the configuration of the communication system 100 according to the first embodiment. The communication system 100 includes an IP (Internet Protocol) network 10, a control device 12, and a first terminal device collectively referred to as a first base station device 14a to a twelfth base station device 14l and a terminal device 16 collectively referred to as a base station device 14. 16a to 16l of the twelfth terminal device are included. In a commercial wireless system, the base station device 14 is also referred to as a repeater. Here, the number of base station devices 14 included in the communication system 100 is not limited to "12", and the number of terminal devices 16 is not limited to "12" and may be more or less than them. May be good. In the first embodiment, it is assumed that the terminal device 16 is not equipped with a positioning function by GPS (Global Positioning System) or the like, but the terminal device 16 may be equipped with a positioning function. The control device 12 is connected to each of the plurality of base station devices 14 via the IP network 10.

As described above, the plurality of terminal devices 16 and the plurality of base station devices 14 correspond to the commercial wireless system, and each terminal device 16 executes voice communication via any of the base station devices 14. .. Each terminal device 16 includes a PTT (Push To Talk) button, and the terminal device 16 with the PTT button pressed down transmits the user's voice to the base station device 14 as call information. When the base station device 14 receives the call information from the terminal device 16, it transmits the call information to the control device 12 via the IP network 10. The control device 12 transmits call information to a plurality of base station devices 14 via the IP network 10. Since the plurality of base station devices 14 transmit the call information, the terminal devices 16 other than the terminal device 16 that has transmitted the call information receive the call information from the base station device 14. In the communication system 100, a group is formed by one or more terminal devices 16, and communication within the group is possible. In such group communication, for example, one-to-many communication such as transmission from one terminal device 16 to a plurality of other terminal devices 16 via the base station device 14 is executed.

FIG. 2 shows the arrangement of channels used in the communication system 100. CH1, CH2, and CH3 common to the base station device 14 and the terminal device 16 are defined. In this figure, an example of the relationship between the channel number and the reception frequency and transmission frequency of the base station apparatus 14 is shown. Further, an example of the relationship between the channel number and the reception frequency and the transmission frequency of the terminal device 16 is shown. In the following description, the reception frequency of the base station device 14 is referred to as an uplink frequency, and the transmission frequency of the base station device 14 is referred to as a downlink frequency. The uplink frequency corresponds to the transmission frequency of the terminal device 16, and the downlink frequency corresponds to the reception frequency of the terminal device 16. In CH1, CH2, and CH3, different uplink frequencies and downlink frequencies are set. Here, CH1 is defined by the combination of the first uplink frequency and the first downlink frequency, CH2 is defined by the combination of the second uplink frequency and the second downlink frequency, and CH3 is defined by the third uplink frequency and the third downlink frequency. It is assumed that it is specified by the combination with. As described above, a plurality of types of downlink frequencies and uplink frequencies that can be set in the plurality of base station devices 14 are defined. Return to FIG.

When the terminal device 16 whose uplink frequency is set to CH1 makes a call, only the base station device 14 whose uplink frequency is set to CH1 can transmit and receive. Therefore, the other base station devices 14 and terminal devices 16 set in CH2 and CH3 can communicate even when CH1 is communicating. Here, the CHs used in each base station device 14 and each terminal device 16 are indicated as "CH1", "CH2", and "CH3". In the following, for the sake of clarity, it is assumed that one group uses CH1, another group uses CH2, and yet another group uses CH3. That is, it is assumed that a different CH is used for each group.

FIG. 3 shows an outline of processing when channel arrangement is used. Each base station device 14 forms a communication area 18 as a communicable area. Specifically, the first base station apparatus 14a forms the first communication area 18a, the second base station apparatus 14b forms the second communication area 18b, and the third base station apparatus 14c forms the third communication area 18c. To form. Further, the first base station device 14a and the third base station device 14c use CH1, the second base station device 14b uses CH2, and the terminal device 16 uses CH1. Therefore, the terminal device 16 can communicate in the first communication area 18a and the third communication area 18c, but cannot communicate in the area covered only by the second communication area 18b. In such a situation, when the terminal device 16 moves, there is no problem as long as it is within the first communication area 18a and the third communication area 18c. However, the terminal device 16 may be temporarily separated from the first communication area 18a and the third communication area 18c due to the influence of the installation status of the terminal device 16, the movement path of the terminal device 16, obstacles, and the like.

When the terminal device 16 moves, it temporarily leaves the first communication area 18a. On the other hand, since the second base station device 14b installed relatively close to the first base station device 14a does not use CH1, it cannot receive the call information from the terminal device 16. During this time, there is no base station device 14 capable of receiving call information from the terminal device 16. As a result, the control device 12 of FIG. 1 cannot receive the call information from the terminal device 16, and cannot transmit the call information to each base station device 14. As a result, sound interruption occurs in each terminal device 16 that receives the call information. Hereinafter, the configuration of the control device 12 for suppressing the occurrence of such a situation will be described, but before that, the configuration of the base station device 14 will be described.

FIG. 4 shows the configuration of the base station device 14. The base station device 14 includes a wireless communication unit 50, a processing unit 52, a communication unit 54, a control unit 56, and a storage unit 58. The wireless communication unit 50 executes communication with the terminal device 16 by executing a process corresponding to the commercial wireless system. When the wireless communication unit 50 receives the call information from one terminal device 16, the wireless communication unit 50 outputs the call information to the processing unit 52. The processing unit 52 outputs the call information to the communication unit 54. A predetermined process may be performed on the call information in the processing unit 52. The communication unit 54 is connected to the IP network 10 of FIG. 1 and transmits call information to the control device 12 via the IP network 10. When the communication unit 54 receives the call information from the control device 12 via the IP network 10, the communication unit 54 outputs the call information to the processing unit 52. The processing unit 52 outputs the call information to the wireless communication unit 50. The wireless communication unit 50 transmits the call information from the processing unit 52 to the terminal device 16.

Further, the communication unit 54 receives information on the uplink frequency and the downlink frequency to be used in the wireless communication unit 50 from the control device 12 via the IP network 10. This can be said to be information about CH to be used in the wireless communication unit 50 (hereinafter, referred to as “CH information”). The control unit 56 stores CH information from the communication unit 54 via the processing unit 52. The storage unit 58 stores the combination of the uplink frequency and the downlink frequency as shown in FIG. 2 and the correspondence relationship with the CH as a table of CH. The control unit 56 acquires the uplink frequency and the downlink frequency corresponding to the CH information based on the CH table stored in the storage unit 58. The control unit 56 sets the acquired uplink frequency and downlink frequency in the wireless communication unit 50.

This configuration can be realized by the CPU, memory, or other LSI of any computer in terms of hardware, and by programs loaded in memory in terms of software, but here it is realized by cooperation between them. It depicts a functional block to be done. Therefore, it is understood by those skilled in the art that these functional blocks can be realized in various forms only by hardware and by a combination of hardware and software.

FIG. 5 shows the configuration of the control device 12. The control device 12 includes a communication unit 30, a call information buffer 32, a storage unit 34, a detection unit 36, a selection unit 38, and a setting unit 40. The communication unit 30 executes communication with a plurality of base station devices 14 via the IP network 10 of FIG. Any terminal device 16 in the group transmits call information on CH1. One or more base station devices 14 set in CH1 receive call information. Each base station device 14 transmits the call information to the control device 12 together with the reception sensitivity when the call information is received. The communication unit 30 receives the call information and the reception sensitivity from each base station device 14. The communication unit 30 selects the base station device 14 having the maximum reception sensitivity, and transmits the call information received from the selected base station device 14 to the plurality of base station devices 14 set in CH1. At that time, the call information buffer 32 stores the call information.

Further, the communication unit 30 not only transmits the call information to the base station device 14, but also transmits the CH information received from the setting unit 40 to the base station device 14. CH information is generated in the setting unit 40. The setting unit 40 sets, for example, CH1 which is a combination of the first downlink frequency and the first uplink frequency in the predetermined base station apparatus 14. Further, the setting unit 40 sets CH2, which is a combination of the second downlink frequency and the second uplink frequency, in the other base station apparatus 14, and further sets CH3, which is a combination of the third downlink frequency and the third uplink frequency. It is set in another base station device 14. At that time, the setting unit 40 refers to the table of CH stored in the storage unit 34.

The storage unit 34 stores various types of information. FIG. 6 shows a table of CHs stored in the storage unit 34. CH1, CH2, and CH3 with respect to the base station device 14 and the terminal device 16 are the same as those in FIG. Further, CH11 is defined by the combination of the second uplink frequency and the first downlink frequency, CH12 is defined by the combination of the third uplink frequency and the second downlink frequency, and CH13 is defined by the combination of the first uplink frequency and the third downlink frequency. It is assumed that it is specified by the combination of. Further, CH21 is defined by the combination of the third uplink frequency and the first downlink frequency, CH22 is defined by the combination of the first uplink frequency and the second downlink frequency, and CH23 is defined by the combination of the second uplink frequency and the third downlink frequency. It is assumed that it is specified by the combination of. The settings of CH11 to CH13 and CH21 to CH23 will be described later. This CH table is also stored in the storage unit 58 of the communication system 100.

FIG. 7 shows a base station apparatus detailed information table stored in the storage unit 34. In the base station device detailed information table, the CH number set in each base station device 14, the coordinate information of the position where each base station device 14 is installed, the receiving radius, and the IP address of each base station device 14 are shown. .. This base station device detailed information table is stored in advance in the storage unit 34. FIG. 8 shows a terminal reception history table stored in the storage unit 34. The terminal reception history table contains signals received from the terminal device 16, for example, the time when the call information is transmitted to the control device 12, the number of the base station device 14 that received the signal from the terminal device 16, and the signal. The number of the transmitted terminal device 16 and the reception sensitivity of the signal in the base station device 14 are shown. This terminal reception history table is written by the communication unit 30. As shown in this figure, each terminal device 16 is given a terminal number (terminal identifier) that can uniquely identify the terminal device 16, and the control device 12 and the base station device 14 are included in the call information. It is possible to determine which terminal device 16 is calling from the terminal number. Return to FIG.

FIG. 9 is a diagram showing an outline of processing by the control device 12. In the example shown in this figure, first, the terminal device 16 transmits the call information to the first base station device 14a while using CH1 at the point P1. The first base station device 14a transmits the received call information to the control device 12. When the terminal device 16 moves from the point P1 to the point P2, the terminal device 16 approaches the vicinity of the boundary of the first communication area 18a. At that time, the detection unit 36 of FIG. 5 stores the reception sensitivity of the call information received by the first base station device 14a and the call information from the terminal device 16 using the first uplink frequency. Obtained from and detects a decrease in reception sensitivity. As a result, the detection unit 36 detects that the terminal device 16 receiving by the first base station device 14a is gradually moving out of the first communication area 18a. Following this, the detection unit 36 detects that the reception sensitivity is smaller than the threshold value, that is, the quality is lower than the threshold value. As described above, the terminal device 16 which is expected to have difficulty in communication due to the movement of the terminal device 16 or the like may be referred to as the "relief target terminal device 16".

The selection unit 38 of FIG. 5 is installed near the first base station device 14a with reference to the base station device installation coordinates, the reception radius, and the set CH number in the base station device detailed information table stored in the storage unit 34. The base station device 14 that has been set and is set to other than CH1 is searched. At that time, the selection unit 38 refers to the terminal reception history table stored in the storage unit 34, and searches for the base station device 14 that has not received the signal retroactively from the present to a certain period of time. As a result, the base station apparatus 14 that does not receive the signal on the currently set CH and can set the first uplink frequency is searched for.

Here, the first base station device 14a to which the terminal device 16 is currently connected is referred to as a base station device N, and the base station device 14 that is the target of the search and is a candidate for changing the channel setting is referred to as the base station device M. Call. Further, the installation coordinates (latitude, longitude) of the base station device N are (Xn, Yn), the reception radius is Rn, and the installation coordinates of the base station device M are (latitude, longitude) (Xm, Ym). , It is assumed that the receiving radius is Rm. It is assumed that the unit of Rn and Rm is km. The selection unit 38 derives, for example, the distance d between the base station device N and the base station device M as follows.

ここで、αは緯度１度あたりの平均的な距離であり、例えばα＝１１１ｋｍであるとする。また、βは経度１度あたりの平均的な距離であり、例えばβ＝９１ｋｍであるとする。基地局装置Ｎと基地局装置Ｍとの間の距離ｄをもとに、選択部３８は、次のように指標Ｐを算出する。

選択部３８は、Ｐがしきい値、例えば「１．５」よりも大きい場合、その基地局装置１４を選択する。これは、複数の基地局装置Ｍのうち、通信エリア１８が基地局装置Ｎの通信エリア１８と連続する基地局装置Ｍを選択することに相当する。ここでは、このような基地局装置Ｎと基地局装置Ｍとの関係を近接という。選択部３８は選択結果を設定部４０に出力する。 Further, the selection unit 38 may derive the distance d from the following approximate values.

Here, α is an average distance per degree of latitude, and it is assumed that, for example, α = 111 km. Further, β is an average distance per degree of longitude, and it is assumed that β = 91 km, for example. Based on the distance d between the base station device N and the base station device M, the selection unit 38 calculates the index P as follows.

When P is larger than a threshold value, for example, "1.5", the selection unit 38 selects the base station device 14. This corresponds to selecting the base station device M in which the communication area 18 is continuous with the communication area 18 of the base station device N among the plurality of base station devices M. Here, such a relationship between the base station device N and the base station device M is referred to as proximity. The selection unit 38 outputs the selection result to the setting unit 40.

For example, the second base station apparatus 14b set in CH2 in FIG. 9 is selected. Since the second base station device 14b has not received the call information from the other terminal device 16, the CH setting of the second base station device 14b is temporarily changed from CH2 to CH22. That is, the setting unit 40 of FIG. 5 changes the second uplink frequency to the first uplink frequency with respect to the second base station device 14b selected by the selection unit 38 while maintaining the second downlink frequency. When the other base station device 14 selected by the selection unit 38 is set to CH3, the setting unit 40 maintains the third downlink frequency with respect to the other base station device 14, and the third Change the uplink frequency to the first uplink frequency. This corresponds to temporarily changing the CH setting of the other base station apparatus 14 from CH3 to CH13. When a plurality of such base station devices 14 are selected, the same processing is performed for each of them. The setting unit 40 generates CH information that reflects the change in the uplink frequency. For example, when the second base station apparatus 14b is changed from the second uplink frequency to the first uplink frequency while maintaining the second downlink frequency, the setting unit 40 generates the CH information indicated by CH22. .. The communication unit 30 transmits CH information to the second base station device 14b.

Here, FIG. 4 is used to explain the process in the base station device 14 that has received the CH information transmitted from the control device 12. It is assumed that the base station device 14 in FIG. 4 is the second base station device 14b. It should be noted that the same processing may be executed even in the other base station apparatus 14. The wireless communication unit 50 can communicate with another terminal device 16 different from the terminal device 16 using CH1 using CH2. When the wireless communication unit 50 does not execute the reception process, the communication unit 54 receives the CH information from the control device 12 via the IP network 10. As described above, since CH 22 is indicated in the CH information, it can be said that the communication unit 54 receives an instruction to change the second uplink frequency to the first uplink frequency while maintaining the second downlink frequency. The communication unit 54 outputs CH information to the control unit 56 via the processing unit 52.

The control unit 56 acquires the uplink frequency and the downlink frequency corresponding to the CH information based on the CH table stored in the storage unit 58. Here, the first uplink frequency and the second downlink frequency are acquired. The control unit 56 sets the acquired uplink frequency and downlink frequency in the wireless communication unit 50. The control unit 56 causes the wireless communication unit 50 to change the second uplink frequency to the first uplink frequency while maintaining the second downlink frequency.

The processing of the control device 12 after the processing of the base station device 14 is completed will be described. FIG. 10 shows an outline of the subsequent processing by the control device 12. The first uplink frequency is common to CH1 in the first base station apparatus 14a and CH22 in the second base station apparatus 14b. Even when the terminal device 16 (terminal device 16 to be rescued) moves from the point P2 to the point P3, the call information transmitted from the terminal device 16 is received by the second base station device 14b. The second base station device 14b transmits the call information to the control device 12. On the other hand, since the second base station device 14b uses the second downlink frequency, the other terminal device 16 that has received the call information from the second base station device 14b in the second communication area 18b uses CH2. The call information from the second base station device 14b is continuously received as it is.

FIG. 11 shows an outline of further processing by the control device 12. This shows the processing following FIG. When the terminal device 16 (terminal device 16 to be rescued) moves from the point P3 to the point P4, it enters the third communication area 18c. Since CH1 is used in the third communication area 18c, the terminal device 16 transmits the call information to the third base station device 14c. Therefore, when the terminal device 16 reenters the communication area 18 of CH1 or when a certain period of time has elapsed after transmitting the CH information to the second base station device 14b, the setting unit 40 of the control device 12 has a second CH information for returning to CH2 is transmitted to the base station device 14b.

The operation of the communication system 100 with the above configuration will be described. FIG. 12 is a flowchart showing a processing procedure by the control device 12. In step S10, the detection unit 36 determines whether or not the communication unit 30 is receiving call information from the base station device N. If receiving (Y in S10), the process proceeds to step S12. In step S12, the detection unit 36 determines whether or not the reception sensitivity from the base station device N is less than the threshold value. If the reception sensitivity is not less than the threshold value (N in S12), after waiting for a predetermined time, the process returns to step S12 and the process is repeated. When the detection unit 36 determines that the reception sensitivity from the base station device N is less than the threshold value (Y in S12), the selection unit 38 determines the CH number X of the base station device N from the base station device detailed information table. Identify (S14). The terminal device 16 to be rescued, which is determined to be Y in step S12, is referred to as the terminal device Z (terminal number Z). Next, the selection unit 38 searches the base station device detailed information table for the base station device 14 that can be received in the vicinity of the base station device N (S16). If there is a receivable base station device 14 (base station device M) (Y in S18) and the base station device M (base station device as a setting change candidate) is not currently receiving (N in S20), the step. Proceed to S22. In step S22, the setting unit 40 refers to the table of CH stored in the storage unit 34, identifies the uplink frequency X of the CH number X, and refers to the receivable base station apparatus M with the uplink frequency (reception frequency). ) Is set to the frequency X (S22). In addition, "not currently receiving" in step S20 may be "not receiving from the terminal device 16 within a certain period of time (for example, 1 hour) in the past". Alternatively, when the current reception is not performed and the average reception time per unit time (for example, 1 hour) in the past fixed time (for example, 6 hours) is equal to or less than a predetermined value (for example, 3 minutes), "current reception is received. It may be determined that "it has not been done".

In step S24, the detection unit 36 receives the call information of the terminal device Z from another base station device 14 having an uplink frequency X, and determines whether or not the reception sensitivity is equal to or higher than the threshold value. To do. If the condition is satisfied (Y in S24), the process proceeds to step S28, and if the condition is not satisfied (N in S24), the process proceeds to step S26. In step S26, the detection unit 36 determines whether or not a certain time has elapsed since the uplink frequency was changed to the base station apparatus M. If the fixed time has not elapsed (N in S26), the process returns to step S24. If a certain time has passed (Y in S26), the process proceeds to step S28. In step S28, the setting unit 40 instructs the base station apparatus M to return the uplink frequency to the original state. When the communication unit 30 is not receiving call information from the base station device N (N in S10), or when there is no base station device 14 that can be received (N in S18), or the base station device as a setting change candidate is If reception is currently being performed (Y in S20), the process is terminated.

According to this embodiment, when the quality of the signal from the terminal device using the first uplink frequency is lower than the threshold value, the second base station device maintains the second downlink frequency while maintaining the second downlink frequency. Since the uplink frequency is changed to the first uplink frequency, the signal from the terminal apparatus can be received by the second base station apparatus. Further, since such processing is executed by the control device, it is possible to suppress the occurrence of a situation in which the terminal device cannot communicate while avoiding the complexity of the processing of the terminal device. Further, in the second base station apparatus, the second uplink frequency is changed to the first uplink frequency while maintaining the second downlink frequency, so that another terminal apparatus receiving the signal from the second base station apparatus can be used. Processing can be continued. Further, since the processing by the other terminal device receiving the signal from the second base station device is continued, the influence on the other terminal device can be reduced.

Further, since the second base station device whose communication area is continuous with the communication area of the first base station device is selected from the plurality of second base station devices, the call information from the terminal device can be received without interruption. Can be done. Further, since a plurality of types of the second downlink frequency and the second uplink frequency that can be set in the plurality of second base station devices are defined, the degree of freedom in the configuration of the communication system can be improved. Further, since the second base station device that does not receive the signal from the other terminal device using the second uplink frequency is processed, the influence on the other terminal device can be reduced. Further, even when the terminal device is moving in the communication area or once it leaves the communication area, the call information can be received or transmitted without interruption. In addition, unused uplink frequencies can be used efficiently.

(Example 2)
Next, Example 2 will be described. The second embodiment relates to a communication system including a plurality of terminal devices that communicate with each other via a base station device, as in the first embodiment. Here, too, when another base station device close to the base station device to which the terminal device (terminal device to be relieved) is connected uses a CH different from the CH used by the terminal device, the terminal is used. The uplink frequency of the device is switched to the uplink frequency of another base station device. In the first embodiment, such switching is executed when the other base station apparatus does not receive the signal from the other terminal apparatus. On the other hand, in the second embodiment, when the priority of the terminal device to be rescued or the group including the terminal device to be rescued is higher than the priority of the other terminal device or the group including the other terminal device. , Perform such a switch. The configurations of the communication system 100, the base station device 14, and the control device 12 according to the second embodiment are the same types as those in FIGS. 1, 4, and 5. Here, the differences from the past will be mainly described.

FIG. 13 shows a priority table stored in the storage unit 34 according to the second embodiment. As shown, the priority for each terminal device 16 is shown. For example, it can be said that the smaller the priority value, the higher the priority. Contrary to this embodiment, the higher the priority value, the higher the priority may be set. Further, instead of the priority for each terminal device 16, the priority for each group including the terminal device 16 may be specified.

The selection unit 38 of FIG. 5 is installed near the first base station device 14a with reference to the base station device installation coordinates, the reception radius, and the set CH number in the base station device detailed information table stored in the storage unit 34. The base station device 14 that has been set and is set to other than CH1 is searched. At that time, the selection unit 38 refers to the priority table stored in the storage unit 34, and in addition to the base station device 14 that is not currently receiving, the priority is lower than the priority of the terminal device 16 whose signal quality has deteriorated. The base station device 14 receiving the signal from the other terminal device 16 having the As a result, a base station device 14 (a base station device 14 that does not cause a great problem even if the reception frequency is changed) that can set the reception frequency to the first uplink frequency is searched for. Subsequent processing of the setting unit 40 and processing of the terminal device 16 are the same as before, and thus the description thereof will be omitted here.

The priority table may not be stored in the storage unit 34 of the control device 12, and the priority table may be stored in the storage unit 58 of the base station device 14. That is, instead of the control device 12 selecting the base station device 14 whose CH setting is changed based on the priority of the terminal device 16, the base station device 14 may perform processing based on the priority. In that case, the selection unit 38 of FIG. 5 refers to the base station device installation coordinates, the reception radius, and the set CH number in the base station device detailed information table stored in the storage unit 34 as before. The base station device 14 installed near the first base station device 14a and set other than CH1 is searched for. At this time, the selection unit 38 sets the search target regardless of whether or not the base station device 14 is currently receiving. As a result, since the signal is received by the currently set CH, the base station device 14 whose reception frequency cannot be set to the first uplink frequency is also searched. Then, the communication unit 30 transmits CH information and the terminal number (terminal identifier) of the terminal device 16 (the terminal device) to be rescued to the searched base station device 14. A priority table is stored in the storage unit 58 of the base station device 14, and when the communication unit 54 receives the CH information, the control unit 56 refers to the priority table and is currently receiving the terminal device. The priority of 16 and the priority corresponding to the terminal number received by the communication unit 54 are specified. Then, if the priority of the terminal device 16 is higher than the priority of the other terminal device 16 currently being received, the reception frequency is changed to the first uplink frequency used by the terminal device to be rescued. On the other hand, the control unit 56 does not change the CH if the priority of the terminal device 16 is lower than the priority of the other terminal device 16. Alternatively, after storing the priority table in both the storage unit 34 of the control device 12 and the storage unit 58 of the base station device 14, the communication unit 30 relieves the searched base station device 14. Instead of the terminal number of the terminal device 16, the priority of the terminal device may be transmitted. That is, the base station apparatus 14 that has received the channel setting change instruction changes the channel setting when the priority of the receiving terminal apparatus 16 satisfies a predetermined condition. Here, the predetermined condition is that the priority of the terminal device 16 being received is lower than the priority of the other terminal device 16 (the terminal device 16 that plans to use the changed channel) related to the channel setting change. Is.

The operation of the communication system 100 with the above configuration will be described. FIG. 14 is a flowchart showing a processing procedure by the control device 12 according to the second embodiment. In step S50, the detection unit 36 determines whether or not the communication unit 30 is receiving call information from the base station device N. If reception is in progress (Y in S50), the process proceeds to step S52. In step S52, the detection unit 36 determines whether or not the reception sensitivity from the base station device N is less than the threshold value. If the reception sensitivity is not less than the threshold value (N in S52), after waiting for a predetermined time, the process returns to step S52 and the process is repeated. When the detection unit 36 determines that the reception sensitivity from the base station device N is less than the threshold value (Y in S52), the selection unit 38 determines the CH number X of the base station device N from the base station device detailed information table. Identify (S54). The terminal device 16 to be rescued, which is determined to be Y in step S52, is referred to as the terminal device Z (terminal number Z). Next, the selection unit 38 searches the base station device detailed information table for the base station device 14 that can be received in the vicinity of the base station device N (S56). If there is a receivable base station device 14 (base station device M) (Y in S58) and the base station device M (base station device as a setting change candidate) is not currently receiving (N in S60), the step. Proceed to S64. In step S64, the setting unit 40 refers to the table of CH stored in the storage unit 34, identifies the uplink frequency X of the CH number X, and refers to the receivable base station apparatus M with the uplink frequency (reception frequency). ) Is set to the frequency X (S64). If reception is currently being performed (Y in S60), the process proceeds to step S62. In step S62, it is determined whether or not the priority of the terminal device 16 being received by the base station device M is lower than that of the terminal device 16 being received by the base station device N. If the priority is low (Y in S62), the process proceeds to step S64 described above. In step S62, "the priority of the terminal device 16 being received by the base station device M is lower than that of the terminal device 16 receiving by the base station device N" is "for a certain period of time (for example, in the past)" in the base station device M. The priority of each terminal device 16 that received the signal within 1 hour) may be added up, and the total value may be lower than the priority of the terminal device 16 that has received the signal in the base station device N ”. The average value of priorities may be used instead of the total value.

In step S66, the detection unit 36 receives the call information of the terminal device Z from another base station device 14 having an uplink frequency X, and determines whether or not the reception sensitivity is equal to or higher than the threshold value. To do. If the condition is satisfied (Y in S66), the process proceeds to step S70, and if the condition is not satisfied (N in S66), the process proceeds to step S68. In step S68, the detection unit 36 determines whether or not a certain time has elapsed since the uplink frequency was changed to the base station apparatus M. If the fixed time has not elapsed (N in S68), the process returns to step S66. If a certain time has passed (Y in S68), the process proceeds to step S70. In step S70, the setting unit 40 instructs the base station apparatus M to return the uplink frequency to the original state. When the communication unit 30 is not receiving call information from the base station device N (N in S50), or when there is no base station device 14 that can be received (N in S58), the terminal device being received by the base station device M When the priority of 16 is not lower than that of the terminal device 16 received by the base station device N (N in S62), the process is terminated.

According to this embodiment, when the second base station device receives a signal from another terminal device using the second uplink frequency, the priority of the terminal device is higher than the priority of the other terminal device. For example, since the change from the second uplink frequency to the first uplink frequency is executed, the frequency of occurrence of the change can be increased. Further, since the frequency of change occurrence increases, it is possible to improve the possibility that the transmission of the outgoing call information continues even when the terminal device leaves the current communication area. Further, in the base station device, if the priority of the terminal device is higher than the priority of the other terminal devices, the change from the second uplink frequency to the first uplink frequency is executed while maintaining the second downlink frequency. , It is possible to eliminate the need to manage the communication status of the base station device in the control device. Further, since it is not necessary to manage the communication status of the base station device in the control device, the processing of the control device can be simplified.

The present invention has been described above based on examples. This embodiment is an example, and it is understood by those skilled in the art that various modifications are possible for each of these components and combinations of each processing process, and that such modifications are also within the scope of the present invention. ..

According to the first and second embodiments, a commercial wireless system is used in the communication system 100. However, the present invention is not limited to this, and for example, a wireless communication system such as a mobile phone other than a commercial wireless system may be used. According to this modification, the degree of freedom of the system can be improved.

According to the first and second embodiments, the control device 12 is configured separately from the base station device 14, and is connected to the base station device 14 via the IP network 10. However, the present invention is not limited to this, and for example, the control device 12 may be integrally configured by being included in any of the base station devices 14. According to this modification, the degree of freedom of configuration can be improved.

According to the first and second embodiments, three types of uplink frequencies and downlink frequencies are defined, and the terminal device 16 uses the first uplink frequency and the first downlink frequency. However, the present invention is not limited to this, and for example, the types of the uplink frequency and the downlink frequency are not limited to "3", and the terminal device 16 may use different uplink frequencies and downlink frequencies. Even in that case, the processes of the control device 12 and the base station device 14 are executed in the same manner. According to this modification, the applicable range can be expanded.

In the first and second embodiments, the frequency is different for each channel, but other channels may be used. For example, a plurality of channels in which the time domain is divided may be prepared, and the channel used by the base station device may be changed according to the channel used by the terminal device to be rescued by the control device 12. For example, the time slot setting of the base station device to which the terminal device moves may be changed according to the time slot of the terminal device to be relieved. Further, the processing may be performed using a plurality of channels in which the combination of the frequency domain and the time domain is divided.

In the first embodiment, when the upstream channel of the base station device to which the terminal device to be rescued moves is unused, the channel setting of the base station device is changed. This is one embodiment of the concept of changing the resource settings according to the equipment that requires the resources when the limited resources of the wireless communication system are not effectively used.

In the second embodiment, the priority of the terminal device to be relieved is compared with the priority of the terminal device using the base station device to which the terminal device to be relieved moves, and the priority is determined according to the comparison result. The channel of the base station equipment is changed. This is one embodiment of the concept of preferentially allocating limited resources of a wireless communication system to high priority equipment.

10 IP network, 12 control device, 14 base station device, 16 terminal device, 18 communication area, 30 communication section, 32 call information buffer, 34 storage section, 36 detection section, 38 selection section, 40 setting section, 50 wireless communication Unit, 52 processing unit, 54 communication unit, 56 control unit, 58 storage unit, 100 communication system.

Claims (3)

A detector that detects the quality of the signal received by the first base station device and from the terminal device that uses the first channel.
When the detection unit detects a signal quality deterioration, the reception channel of the second base station apparatus is changed from the second channel to the first channel, and the transmission channel of the second base station apparatus is not changed. ,
A control device comprising. A control method used in a control device.
A signal received by the first base station device and from a terminal device using the first channel.
Steps to detect signal quality and
When a signal quality deterioration is detected, the reception channel of the second base station device is changed from the second channel.
The step of changing to the first channel and
Including
The control method, wherein the changing step does not change the transmission channel of the second base station apparatus. A step of detecting the quality of a signal received by the first base station device and from a terminal device using the first channel,
A program for causing a computer to execute a step of changing the reception channel of the second base station apparatus from the second channel to the first channel when a signal quality deterioration is detected.
The changing step is a program characterized in that the transmission channel of the second base station apparatus is not changed.

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